[LINK] "Europa’s Acidic Oceans May Prohibit Life"

[rfmcdonald]

Tammy Plotner's Universe Today post manages to neatly link up the ongoing acidification of the oceans of Earth produced by the greenhouse effect with the possibility that the oceans of Europa may have been rendered sterile by the same sort of phenomenon.

Check out liquid water on Earth and you’ll find some form of life. As a given, scientists hypothesize other worlds which contain water should also support life. According to recent studies, Europa’s ocean might even be saturated with oxygen – further supporting these theories. However, there’s a catch. Like Earth, surface chemicals are continually drawn downward. According to researcher Matthew Pasek, an astrobiologist at the University of South Florida, this could constitute a highly acidic ocean which “is probably not friendly to life — it ends up messing with things like membrane development, and it could be hard building the large-scale organic polymers.”

According to Charles Choi of Astrobiology Magazine, “The compounds in question are oxidants, which are capable of receiving electrons from other compounds. These are usually rare in the solar system because of the abundance of chemicals known as reductants such as hydrogen and carbon, which react quickly with oxidants to form oxides such as water and carbon dioxide. Europa happens to be rich in strong oxidants such as oxygen and hydrogen peroxide which are created by the irradiation of its icy crust by high-energy particles from Jupiter.”

Although it’s speculation, if Europa produces oxidants, they may also be drawn toward its core from ocean motion. However, it might be infused with sulfides and other compounds creating sulfuric and other acids before supporting life. According to the researchers, if this has happened for just half of Europa’s lifetime, the result would be corrosive, with a pH of about 2.6, “about the same as your average soft drink,” Pasek said. While this wouldn’t prohibit life from forming, it wouldn’t make it easy. Emerging life forms would have to be quick to consume oxidants and build an acid tolerance – a process which could take as much as 50 million years.

Are there similar acid-lovin’ lifeforms on Earth? You bet. They exist in acid mine drainage found in Spain’s Rio Tinto river and they feed on iron and sulfide for their metabolic energy. “The microbes there have figured out ways of fighting their acidic environment,” Pasek said. “If life did that on Europa, Ganymede, and maybe even Mars, that might have been quite advantageous.” It is also possible that sediments at the bottom of Europa’s ocean may neutralize the acids, even though Pasek speculates this isn’t likely. One thing we do know about an acidic ocean is that it dissolves calcium-based materials such as bones and shells.

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For now, we’ll look to Europa and wonder at what may exist below its frozen waves. Is there an acid-loving form of life just waiting to bubble to the surface for us to find? Right now researchers are developing a drill which could assist in looking for extreme forms of life. The “penetrator” could eventually be part of a Europa exploration mission which could begin as early as 2020.